Patent GB-324106-A (GB)
Title: Telegraph systems
IPC: H04L7/00
Filed: 1928-10-18
Abstract: 324,106. Standard Telephones & Cables, Ltd., and Clokey, A. A. Oct. 18, 1928. Synchronous movements.- Telegraph apparatus is synchronized by interrupting signalling, bringing the cable to a predetermined electrical condition and then transmitting a synchronizing signal. The receiver is stopped during the' predetermined interruption, corrected in speed, and restored to operation. Transmitter, Fig 2. Normally, distributor brushes 4, 5 successively connect the tongues of the transmitters in channels A - - D to a cable 1, and transmit impulses in accordance with the perforations in the tapes. At the end of a predetermined period cams 21, 22 close contacts 27, 28 simultaneously, while the brushes are travelling between segments 24, 25, and the speed of the cams is so regulated that the contacts remain closed during one and a half revolutions of the brushes. The brush 5 then earths a segment 26 through a common ring 6, and thus closes a circuit through a relay 9, a conductor 29, a resistance 30, and the contacts 28, 27 to a battery 31. The relay operates, locks up over its front contact, and remains operated until the brush contacts with the release segment 25. A relay 10 is operated in a similar way from the segment 24 and released from a segment 23. Meanwhile the brush 4 crosses the transmitting segments. No signals are sent. as the tape transmitters are locked by magnets 34, 35 energized over the two lower tongues and contacts of the relay 9, and by magnets 36, 37, similarly energized by the relay 10. The relay 9 also disconnects the first and second segments of the channel A from their transmitting tongues and connects them to earth over contacts 38, 39, and the fourth segment is connected to positive battery over a contact 40. Similarly segments in the channel B are switched by the relay 9, and segments in channels C, D by the relay 10, to earth and to positive or negative battery to transmit successive impulses of opposite polarity. The transmitter is returned to normal operation by the release segments 23, 25. Receiver, Fig. 3. Cams 70, 71 close contacts 72, 73 simultaneously with the corresponding contacts at the transmitter. When a distributor brush 16 contacts with a segment 45, it closes a circuit from earth through. a common ring 46, the segment 45, a relay 53, a conductor 54, a resistance 57, and the contacts 72, 73 to a battery 58 to operate the relay 53 which locks up over its upper armature. The relay completes over its lower contacts the circuits of locking-magnets 48, 49 in the channels A, B. A relay 52 is similarly operated from a segment 43 and closes the circuits of locking-relays 50, 51 in the channels C, D. Synchronizing. The positive and negative impulses from the segments associated with the channels A, B, C wipe out the distorting influence on the cable of previous signals, and synchronizing segments 59, 60 are inserted between the second and third and the fourth and: fifth receiving-segments of the channel D. When the receiver is synchronized the synchronizing-segments, bein, equidistant between receiving-segments, receive current reversals. Otherwise either positive or negative impulses are applied to the synchronizing-segments, which are connected, through contacts 61 on the relay 52 to a polar relay 62, which therefore moves its tongue to the left or to the right. The relay tongue closes a circuit from a. battery 63 to one of correcting magnets 64, 65 which steps the ratchet wheel 66 to the right to movea weight 19 on a tuning fork 18 towards the end of the tine, or a ratchet wheel 67 to the left to move the weight in the opposite direction. Modifications. A vacuum-tube regenerative tuning-fork is used; the receiving-distributor runs slightly faster or slower than the transmitter and is corrected in one direction only; primary and secondary correction is used asdescribed in Specification 213,302 ; the contacts are closed by rotating cams or vibrating reeds; the cable circuit is earthed or opened for the period preceding the synchronizing impulse ; a single impulse is used.